It has been known in diaphragm cells to feed current into the cathodes initially through grid bars. The current travels from the grid bars through side plates and then across flanges through tube sheets which then distribute current to the cathode tubes. Thus in U.S. Pat. No. 3,390,072 there has been disclosed a diaphragm cell having grid bars for current distribution, which grid bars are secured, at about mid section of the outer surface, to the diaphragm cell side plates. Such side plates form a portion of the outer housing of the diaphragm cell. The current flow can then be continued in the manner as discussed hereinabove, i.e., through flanges to the tube sheets.
It has been known to provide plug welded rods between the side plates and the tube sheets which can reinforce these members of the cell. Such rods, located below the upper and lower flanges, can be welded to the outer face of the tube sheet, extend across the gap between side plate and tube sheet, and continue through holes in the side plate. The outer end of the rods are then welded to the side plate. Such rods, positioned thereby in a manner parallel to the flanges between the side plates and the tube sheets, may therefore provide supplemental current flow along with providing structural reinforcing characteristic.
It would nevertheless be desirable to provide for a more even cathode temperature distribution. Such could enhance economy of cathode operation as well as desirably contribute to current density distribution. It would be most desirable to obtain all of these benefits while retarding to eliminating any possibility of cell stress corrosin cracking.